| Cotton straw returning by carbonization is a better way of straw returning,which can improve soil,promote crop growth and increase yield.Through the field comparative experiment,taking ash desert soil-cotton planting system as the research object,the effects of interaction between cotton stalk carbon and nitrogen fertilizer in ash desert soil on cotton growth,nitrogen fertilizer use efficiency and soil fertility were studied,and the effects of interaction between cotton stalk carbon and nitrogen fertilizer on cotton growth,nitrogen fertilizer use efficiency and soil fertility were determined.It provides reference for Xinjiang cotton straw resource utilization,soil improvement and agricultural production.The research results are as follows:(1)Compared with field conventional treatment(NPK),low amount of cotton stalk carbon/N interaction(B1N)reduced plant height and stem diameter at seedling stage,decreased dry weight and leaf area of cotton roots,stems and leaves from seedling stage to boll-setting stage,and increased stem diameter,dry weight and leaf area at floc opening stage.The nitrogen and phosphorus uptake per plant of cotton were increased by 42.73%and 73.75%respectively.Decreased the content of alkali-hydrolyzable nitrogen in 0-60cm layer by3.73%-32.16%,and significantly increased the content of available phosphorus in 0-100cm layer by 15.12%-103.96%.The yield per mu of cotton was increased by 1.27%,the absorption efficiency of nitrogen fertilizer and phosphorus fertilizer was significantly increased by 25.96%and 4.75%,respectively,and the partial productivity of nitrogen fertilizer was increased by 0.9kg/kg.(2)Compared with field conventional treatment(NPK),the stem diameter from seedling stage to boll setting stage was decreased by BCN interaction(B2N),while the stem diameter at floc opening stage was increased by 22.60%.The dry weight and leaf area of cotton root,stem and leaf from seedling stage to boll-setting stage were decreased,and the dry weight and leaf area of cotton root,stem and leaf were increased at floc opening stage.The nitrogen and phosphorus uptake capacity of cotton per plant were increased by 83.69%and 99.21%.In the 0-40cm layer,the soil electrical conductivity was significantly increased by 22.48%-26.05%,the soil alkali-hydrolyzable nitrogen content in the 0-20cm and 40-80cm layers was decreased by 21.69%,and the soil available phosphorus content in the 0-20cm layer was decreased by 15.95%.The per mu yield of cotton seed cotton was significantly decreased by 14.96%,and the absorption efficiency of nitrogen fertilizer and phosphorus fertilizer was significantly increased by 48.87%and 6.28%,respectively.(3)Compared with field conventional treatment(NPK),B4N had no significant effects on cotton plant height and SPAD.The dry weight of root after flowering and stem and leaf bolling stage was significantly increased.It had no significant effect on buds,flowers and bolls.Significantly increased the nitrogen uptake by 27.63%and phosphorus uptake by 49.65%per plant;The electrical conductivity of 0-40cm layer was significantly increased by 18.42-55.58%,the content of available P in 0-100cm layer was significantly increased by 150.78%-33.79%,and the content of total nitrogen in 0-100cm layer was significantly increased by 12.75%.The per mu yield of cotton seed cotton was decreased by 4.92%,the nitrogen absorption efficiency was significantly increased by 6.46%,and the partial nitrogen productivity was increased by 0.9kg/kg.(4)Compared with conventional fertilization(B1N),the stem diameter at seedling stage was significantly increased by 30.0%and decreased by 1.99%-5.75%from bud stage to floc opening stage in the treatment of B1N1 and low nitrogen.The dry weight of root,stem and leaf from seedling stage to anthesis stage of cotton was increased,and the dry weight of root,stem and leaf was decreased at floc opening stage.The dry weight of bud and flower was significantly reduced.The nitrogen uptake per plant was increased by 0.77%,and the phosphorus uptake per plant was decreased by 7.24%.The soil electrical conductivity in the 0-20cm layer was significantly increased by 29.16%,and the soil alkali-hydrolyzable nitrogen content in the 0-20cm and 40-100cm layers was significantly decreased by 10.59-26.56%.The per mu yield of cotton seed cotton was significantly decreased by 32.55%,the absorption efficiency of phosphorus fertilizer was decreased by 4.16%,and the partial productivity of nitrogen fertilizer was increased by 0.3kg/kg.(5)Compared with conventional fertilization(B1N),the stem diameter at seedling stage was significantly increased by 30.0%and decreased by 1.99%-5.75%from bud stage to floc opening stage in the treatment of B1N1 and low nitrogen.The dry weight of root,stem and leaf from seedling stage to anthesis stage of cotton was increased,and the dry weight of root,stem and leaf was decreased at floc opening stage.The dry weight of bud and flower was significantly reduced.The nitrogen uptake per plant was increased by 0.77%,and the phosphorus uptake per plant was decreased by 7.24%.The soil electrical conductivity in the 0-20cm layer was significantly increased by 29.16%,and the soil alkali-hydrolyzable nitrogen content in the 0-20cm and 40-100cm layers was significantly decreased by 10.59-26.56%.The per mu yield of cotton seed cotton was significantly decreased by 32.55%,the absorption efficiency of phosphorus fertilizer was decreased by 4.16%,and the partial productivity of nitrogen fertilizer was increased by 0.3kg/kg.In conclusion,the suitable interaction of cotton stalk carbon and nitrogen(1%carbon application,300kg/hm~2N)can improve soil nutrients,cotton yield,partial productivity of N and agronomic efficiency of N,and it is the suitable application method of cotton stalk carbon and nitrogen fertilizer in ash desert soil.Considering comprehensively from the Angle of reducing nitrogen fertilizer application and improving soil rapidly,the interaction between cotton stalk carbon and nitrogen with a higher amount(210kg/hm~2,application amount of carbon 2%)was better,which had little effect on cotton yield,was conducive to improving nitrogen fertilizer absorption and apparent utilization rate,had a better effect on soil improvement,and increased soil carbon fixation.It is a good way to improve soil,reduce nitrogen fertilizer application and carbon emission,but the investment is high.From the perspective of maximum carbon sequestration,rapid soil improvement and soil nutrient supply,the interaction of high amount of cotton stem carbon and nitrogen(4%carbon application amount,300kg/hm~2nitrogen fertilizer)is a better way to reduce carbon emissions and soil improvement,but the input is very high. |
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